You can usually find some decent v hull jon boats on craigslist with (late 90's, early 2000's motor) 15-25 hp engines for around $1500 (14-15 foot jon boats with power). I see those every now and then. If your looking to spend less you could pick up a 2.5-3.5 hp outboard for around $500. I have a 3.5 hp carbureted 2 stroke (2003) and I've put that on the back of a flat back canoe, the 12' v hull jon boat and a 12" flat bottom jon boat. With 2 adults in the flat bottom jon boat we hit 9-10 mph, single person with loads positioned correctly I hit 12mph. The v hull jonny is much heavier, max speed with 3 adults was 5.5mph and flat back canoe was about the same as the flat jon boat. If that doesn't float your boat 3500-4500 could get you a decent Carolina skiff (J-14 with 25hp four stroke). The canoe and 3.5hp setup works real good for the lagoon, especially in that skinny water, if you have 2 people in the canoe, hull slap is minimal.